In general, acupressure is a hand therapy that aims to promote health or treat diseases by applying a pressure to a predetermined part of the surface of a human body, and different effects are provided by increasing or decreasing acupressure power or keeping the acupressure power constant.
A general acupressure treatment is achieved by vertically applying a pressure to a predetermined part, keeping the pressure constant for a predetermined time, and then releasing the pressure. In order to keep the pressure constant, a process of measuring the current pressure and correcting the pressure is needed.
The conventional automatic heaters provide acupressure power using a pressing force applied to an acupressure section according to a weight of a user, and a magnitude of the acupressure power is proportional to a magnitude of the weight, and for the same weight, the magnitude of the acupressure power varies according to the distribution of loads applied to the product.
Here, the distribution of loads refers to difference in the degree to which the weight of the user is assigned in each position of the product. When the load due to the weight of the user is concentrated on a massager, the magnitude of the acupressure power increases, and when the load due to the weight of the user is concentrated on other structures, such as foam, the magnitude of the acupressure power decreases.
When the acupressure section is lifted, the load is concentrated on the massager in comparison to that of the previous state, so that the magnitude of the acupressure power is increased. In contrast, when the acupressure section is lowered, the load is concentrated on other structures excluding the massager, so that the magnitude of the acupressure power is decreased. By using this principle, the magnitude of the acupressure power is controlled.
The conventional automatic heaters adopt a concept of acupressure power control using a vertical height of the acupressure section. However, since there is no device to measure the current acupressure power, an increase or decrease in the acupressure power is only achievable based on the current acupressure power, so the conventional automatic heaters cannot implement the acupressure power at a specific value.
In addition, the conventional automatic heaters have an acupressure power control algorithm in which a horizontal position corresponding to a position of a spine bone of the user is measured through a process of a body scan, a vertical height corresponding to a massage strength at the corresponding position is calculated, and the acupressure section is controlled to be moved to a vertical position corresponding to the vertical height whenever the acupressure section passes through the corresponding horizontal position.
However, when the user moves during the massage and thus the position of the spine bone is changed, or the user is changed with another user, the vertical position also needs to be changed according to the changes. However, the massage process is controlled to use a previously stored vertical position, thus causing a difference between an actual acupressure power and an intended acupressure power.
This is because the massage process is performed with acupressure power corresponding to a previously-stored position of a spine bone, that is, a previously-stored vertical position of the acupressure section even when the position of the spine bone of the user is changed, and there is a limitation in obtaining an optimum effect of massage with a result in which a displacement value according to a spine bone displacement caused by the user is not reflected.